import numpy as np
import matplotlib.pyplot as plt
points = np.arange(-5,5,0.1)
xs,ys = np.meshgrid(points, points) 
z = np.sqrt(xs ** 2 + ys ** 2)
plt.imshow(z, cmap=plt.cm.gray);plt.colorbar()
plt.title("Image plot of sqrt values")
plt.show()